Event-driven power-law relaxations in weak turbulence

Year: 2009

Authors: Silvestri L., Fronzoni L., Grigolini P., Allegrini P.

Autors Affiliation: Dipartimento di Fisica ‘‘E. Fermi,’’ Universita` di Pisa and INFM CRS-SOFT, Largo Pontecorvo 3, 56127 Pisa, Italy; Center for Nonlinear Science, University of North Texas, P.O. Box 311427, Denton, Texas 76203-1427, USA; Istituto dei Processi Chimico Fisici del CNR Area della Ricerca di Pisa, Via G. Moruzzi 1, 56124 Pisa, Italy

Abstract: We characterize the spectral properties of weak turbulence in a liquid crystal sample driven by an external electric field, as a function of the applied voltage, and we find a 1/f noise spectrum S(f)∝1/fη within the whole range 0<η<2. We theoretically explore the hypothesis that the system complexity is driven by non-Poisson events resetting the system through creation and annihilation of coherent structures, retaining no memory of previous history (crucial events). We study the time asymptotic regime by means of the density ψ(τ) of the time distances between two crucial events, yielding η=3−μ, where μ is defined through the long-time form ψ(τ)∝1/τμ, with 1<μ<3. The system regression to equilibrium after an abrupt voltage change experimentally confirms the theory, proving violations of the ordinary linear response theory for both η>1 and η<1. Journal/Review: PHYSICAL REVIEW LETTERS

Volume: 102 (1)      Pages from: 014502  to: 014502

More Information: P. G. thanks ARO and Welch for financial support of this work through Grants No. W911NF-08-1-0177 and No. B-1577, respectively.
DOI: 10.1103/PhysRevLett.102.014502

Citations: 55
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